Sleep is a complex behavior regulated by both homeostatic and circadian mechanisms. The neural circuits involved in sleep homeostasis are not well described yet. However, it has been previously proposed that GABAergic inputs to the large lateral ventral neurons (lLNvs) of Drosophila may be responsible of informing those highly integrative arousal neurons about the sleep homeostat status. On the other hand, the current paradigm proposes that the main circadian pacemaker of the Drosophila brain, the small lateral ventral neurons (sLNvs) have only minor influence in the control of sleep behavior.
Starting from this point, our aim is to describe the mechanisms of GABAergic inhibition in both sLNvs and lLNvs, their influence on sleep behavior and their role on the sleep homeostat. For this, we have performed specific genetic manipulations and quantified sleep behavior under basal and sleep deprivation conditions. Moreover, we have collected preliminary electrophysiological recordings to identify the extent of the role of the neurotransmitter GABA in the neuronal circuit studied, given that our final goal is to describe this network in detail. Our findings confirm that the lLNvs receive information about the sleep homeostat status via the GABA A receptor Rdl through a complex neuronal circuit. They also suggest that the sLNvs are involved not only in the control of the circadian sleep timing, but also can regulate the
quantity and quality of sleep.